The invention relates to large liquid containers and more particularly to reservoirs having a floating cover assembly.
Throughout the world the necessity for a pure water supply is essential to sustain the life and health of mankind. Many areas of the world have population concentrations where local water resources cannot support the demands placed on the limited supply. Through the ingenuity of engineers, construction of very complex water transport and storage systems have been successfully implemented to make remote water sources accessible to population centers hundreds of miles away from the water source. Increased demands for the limited water resources continue to challenge engineers for unique solutions to enhance water supplies. Drought weather patterns aggravate the situation where preserving and utilizing the precious resources have become of paramount importance to the government and the populous at large.
In order to conserve water resources, many reservoirs are having floating cover assemblies installed to cut down on evaporation and contamination of the water in the reservoir. There is a great body of prior art with respect to floating reservoir covers and the advantages of and methods for imparting tension into the flexible membrane covers to make them function as desired.
U.S. Pat. No. 3,815,367 teaches a method of imparting tension to the central portion of a floating cover using a plurality of weight towers around the outside of the reservoir. This patent describes what is commercially known as a "mechanically tensioned floating cover". U.S. Pat. No. 4,971,217 principally teaches the use of slip ring connections in the reservoir cover system design. This cover system could employ the tensioning system taught in this patent application. U.S. Pat. No. 5,108,225 teaches the use of a mechanically tensioned floating cover in conjunction with an elevated wall reservoir. This cover system could also employ the tensioning system taught in this patent disclosure.
It is important to note that the present state of the art in commercial practice of mechanically tensioned floating covers universally and exclusively utilize "weight towers" to provide the tensioning means. The use of floating covers for reservoirs has been around for approximately 25 years. The weight towers extending up from the top surface of the surrounding containing wall of the reservoirs are found objectionable for both practical reasons and cosmetic reasons. They appear as a row of numerous four to fourteen foot high posts extending upwardly from the containing wall of the reservoir. Aesthetically, they are objectionable. The individual cost of the numerous towers that are laterally spaced from each other around the periphery of the surrounding containing wall is relatively costly. Added to this is the expense of installing these numerous weight towers. The weight of these towers is also a costly consideration when they have to be shipped to distant installation sites.
It is an object of the invention to provide a novel floating reservoir cover tensioning system that eliminates the unsightly weight towers used in state of the art floating reservoir cover installations.
It is also an object of the invention to provide a novel floating reservoir cover tensioning system that utilizes constant force springs mounted in a low profile case or housing for providing the required tension to the periphery of the floating reservoir cover.
It is another object of the invention to provide a floating reservoir cover tensioning system whose tensioning assemblies are relatively inexpensive to install.
It is a further object of the invention to provide a novel floating reservoir cover tensioning system whose tensioning assemblies are much smaller in size and weigh much less than existing prior art tensioning assemblies.
It is an additional object of the invention to provide a novel floating reservoir cover tensioning system that is more economical to manufacture and market than existing floating reservoir cover tensioning systems.